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Both come from the greatest German performance car manufacturers and share the same 600 hp power. That's where the similarities end though—which one will turn out to be more effective on track?

Lamborghini Miura didn't need to look the way it did. It was only that Marcello Gandini and his fellow twenty-somethings wanted to make a car wider, lower, and oh-my-God-it's-nothing-like-I've-seen-before-er than anything else; the definitive supercar. You don't really buy a supercar for its performance, as there is little chance you will ever explore its true limits, both because there aren't too many places where you can actually do this, and because your name isn't Nico Rosberg, Fernando Alonso, or any other that would indicate that you really know how to handle a 700 hp RWD beast. Let's be honest here, it's an ego purchase; and where ego counts, it's the most dramatic, exotic, and sexy effect that counts. It is not the owners of the trackday curios that pull the best girls. With today's knowledge of vehicle dynamics, the only moment in which the prolonged hood, giant wings and active aero actually work, is in front of a club or a restaurant, not on the track.

Or do they? Maybe I'm just being unduly sarcastic and all these talks of great heritage, beguiling creases, and tight cabins with no space to leave your luggage really are a necessary sacrifice. There's only one way to find out; and to do that, we need a racetrack, a lap timer and two cars to compare. The one that will challenge the supercar status quo is the 2017 Audi RS 6 Avant performance. This famous über-wagon, pitifully still unavailable stateside, is regarded as the definitive Ferrari-beater Q-car, whose history can be traced back directly to the times of the Porsche-stuffed Audi RS2 of the early 1990s. In 2016, the recipe for its successor once again cites one humdrum family wagon and a set of highest quality racing componentry. Together, they make for a remarkably versatile machine, perfectly handling a family school run in the morning, a cosseting ride for a rendezvous in the evening, a continental trip, and a track time trial. With the finest leather finish to shame a Maybach, an unequalled cargo space of 20 cubic feet, and, ah yes, a GODDAMN 605 HP TWIN-TURBO V8, RS 6 receives top marks as a van, a limousine, and... a supercar?

The car to prove RS 6 wrong and to defend the honor of the performance exotica will be a BMW M6 featuring the 2017 Competition Package. You could argue that there are fitter competitors out there, but if this Bimmer doesn't live up to the supercar hype, then I really don't know what does. There are certain reasons for which this grand Bavarian GT is the most suitable for this comparison. You see, seemingly in response to Audi's Performance line, which gives a bit more edge and speed to its RS models, the recently premiered BMW's Competition Package hides some game changing features: tick one unremarkable box on the M6's option list and its steering gets meatier, stability control more encouraging, suspension stiffer, and wheels flashier. Down the line, a standard exhaust system paves the way for a competition (but, of course) Akrapovic unit, while the 4.4 Twin-Turbo V8 gets a power bump from 560 hp to an RS 6-equalling 600 hp. Ok, so the Audi wagon may still have an advantage of 5 hp, but really, at this level of performance, such a difference is negligible.

Remarkably, after this quick round of indoor tuning, the data sheets of both cars seem identical: The power and torque curves of their twin-turbo V8s follow a nearly identical line, they share the same 190 mph top speed, they both have automatic transmissions, they brake from 60 mph to standstill on the same distance (a supercar-worthy 115.5 ft, credit to huge carbon-ceramic disc brakes). They even take nearly the same space on the road: measuring 196 inches on the long side and 76.2 inches across, Audi's largest wagon is only 3.3 inches longer and 1.6 inches wider than BMW's two-door. If RS 6 was on sale in the US, it would probably be sold for around the same money as M6 is, with the price for this particular example elevated by the rich equipment to around 150,000 USD.

And so, with only the body style left to distinguish between these two, we can find out if it's really the silhouette that makes the difference. At least, I thought it'd be this easy, but no; there are still some key differences to keep in mind. As cars and dating sites go, numbers don't tell the whole story. A brief look into the spec sheet reveals that Audi has an important advantage of the AWD quattro drive, which, even if able to shift 70% of the power to the front or 85% to the rear limited-slip diff, is there to keep the car neutral in all possible situations. At the same time, the additional cogs are one of the reasons for which the Audi weighs a rather gargantuan 4464 lbs., or 214 lbs. more than M6. Still, this means that the Big M tips the scales at 4250 lbs., which is hard to excuse for such a sleek machine.

But enter M6's cabin and you'll instantly understand where all this car obesity comes from. Isn't it actually the performance cars themselves that should be blamed for letting their own species become pointless? You know, like, dramatic and ready to take no compromises from the outside, but still pretty pampering and ready to serve every whim inside, if you ask me. When exactly did a high-end sixteen-speaker audio, heated seats and steering wheel, a two-zone a/c, and a tv tuner become a norm for performance cars? It's certainly not that M6 is an exception here, as most of these features can be easily found in every new mid-engined Ferrari or McLaren. Just like in Maranello's and Woking's finest, here, the rally world-sourced Alcantara, lightweight details, and carbon fiber are also present and are used for the same, solely aesthetic reasons.

So what's the difference between M6 and RS 6 from the driver's perspective? It's not that dramatic, if not even confusing, if you take into consideration that it's the Avant that has a perforated steering wheel, a galvanized gear knob, and race buckets in the front, while it's the racey BMW that has wood trim and a ski bag in the rear. Some things don't change though: as a coupe, M6 gets your bun closer to the ground than the Audi, which makes an impression of more of an SUV from this perspective, while the people sitting in the rear get just as little space as one can imagine when looking at this sloping roofline; it's really tight in the 6-series. Those who believed that BMW's wizards could really flout the laws of physics after the corner-defying X6 M, are in for a disappointment.

Just like in any modern performance car, it takes a few knob tweaks and a few clicks in the unfathomable depths of the onboard menus to morph M6 and RS 6 from easygoing all-rounders to ruthless track terrorists. On the cushy highway track commute in the RS 6, the Tiptronic eight-speed gearbox never allows the muted engine to pass 2000 rpm and 20 mpg, letting the perfectly isolated cabin be filled with the quality sound of the Bang & Olufsen audio. On the track, though, the RS begins to depart from you usual Audi A6 experience. Advance from Comfort, through Auto, to Dynamic mode, and things get really, err, dynamic. It's like a Joe Public that suddenly finds superpowers when things get nasty. Now, the hitherto silky steering requires some proper force to move the wheel, while the pneumatic suspension for once uses its great capacity in order not to ease out the road creases, but to find truly extreme levels of stiffness to keep the car planted on all occasions.

And yet not that much changes on the drivetrain front. Despite the infinite capabilities of this 605 hp motor, even with the V8's volume turned up to 11, I'm sorry to say it just stays an uninspiring set, bar the shock of the sheer power generated under the hood. Everything onboard, the motor, the transmission, the quattro system, is there to prove its point - and nothing beyond that. The steering does an amazing job of letting you control the situation with little effort, but that makes the wheel feel just plain numb. The auto tranny works brilliantly in everyday situations, but it clearly isn't intended for track use; the four-ringed ECU brain doesn't understand what it's expected to do here, and if you try to take matters into your own hands, you quickly end up irritated by the tiny flaps attached to the steering wheel, which you just can't localize when you need to select a gear. The upgraded parts from the Performance line try to inject some enjoyment into the drive, but there's no way around saying it's not the sportscar type of fun this kind of muscle-wagon can deliver, or any other repmobile-turned-god for that matter.

But, oh boy, is this thing effective. The quattro drive doesn't allow for any kind of wheelspin at the starting line, nor any kind of tailslide for the following two miles of the never-ending section of corners that form a lap of this relatively slow technical track. If, on this damp slippery asphalt, this family-hauler-turned-go-kart would finally give in to the laws of physics, it'd be the front axle that might lose the fight first and allow for an early-signaled understeer, just like the engineers prefer the cars to behave these days to let the weaker drivers control the situation in an emergency. A moment of drama-free precise throttle management and I'm back on the finish line with the time of 1:08.47. It felt sluggish from the inside, but appears improbably quick in reality. To put it into a context, it's a better result than I achieved here with Mercedes-AMG C63 S or BMW M4.

Time for M6 then. Turn on the engine and the cabin is immediately filled with the audial drama I've been dreading for in the first part of the day. From the perspective of a car like Lotus, or even Porsche 911, M6 is a sportscar just like a Ralph Lauren shirt is an item of clothing to actually play polo in; but deep under this poetically sculpted metal finished in frozen white there lies a true BMW. M6 is focused, responsive, rough, stiff, alert, and, most importantly, playful. You know it's a true supercar if the experience is at least a bit more theatrical than it really needs to be, so at this point you're ready to accept the fact that the best part of the soundtrack actually comes from car's speakers, not four black exhaust tips. As the Competition Pack eliminates the alternative of the manual gearbox (competition means it's all about the pace, mind), I set the M DCT Drivelogic to its sharpest position, I confidently cut the traction control off, and I'm away for the lap. Ten seconds later I'm already facing the direction of the track with my back and eyes set on the starting line from the wrong side. I spun on the first corner. Turns out this 193 in. long behemoth is far friskier than you'd expect it to be, especially after the seemingly glued-to-the-surface RS 6. With the mission to put all of the 600 hp solely through the rear M diff, M6 appears to be just as much of a brutish drifting tool as any other German muscle car from BMW's or AMG's stable. Fun? Sure. Effective? Less so. No wonder even M's boss Frank van Meel hints that the M6's successor will join the AWD game. If you can't argue with numbers, this duel ends up with very awkward silence: BMW's coupe comes second, with the time of 1:09.44, or 0.97 second behind the Audi's missile.

Of course, the final standings could have been different on another track, as the records from circuits around the world suggest, possibly they could have been different even here but for the slippery conditions favoring the neutral quattro drive, or in some more skilled hands than mine. Anyway, this leaves a lesson to learn for all. For starters, it's M6 that's called a gran turismo, but these are the cars like RS 6 or the new super-SUVs that are the new GTs: blending luxury with the ability to tackle whole countries in a matter of hours, frighteningly effective on the winding stuff, brimming with swag, and now enjoying extra luggage space.

Still, when it comes to performance cars, the low-slung coupes are still the weapons of choice. Even if, remarkably, their sleek silhouettes don't give them a strategic advantage, from the two, it was still the M6 that felt more in place on the track, like a natural-born athlete versus the RS 6 Hulk-machine.

Why will nobody make a true performance car in a wagon body, you ask? Well, there's at least one company that knows how to do it, and this is BMW. M6 is directly related to the legendary M5, which in the past had its moments of coming in wagon flavor, too. The reasons these episodes were brief was that hardly anyone bought this five-door M. The wagons may be as fast as supercars these days, but even now no one really wants them to bring supercar's driving sensation.